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#include "ltfat.h"
#include "ltfat_types.h"
LTFAT_EXTERN void
LTFAT_NAME_COMPLEX(iwfac)(const LTFAT_COMPLEX *gf, const ltfatInt L, const ltfatInt R,
const ltfatInt a, const ltfatInt M, LTFAT_COMPLEX *g)
{
ltfatInt h_a, h_m;
ltfatInt rem, negrem;
LTFAT_REAL scaling, *sbuf, *gfp;
LTFAT_FFTW(plan) p_before;
const ltfatInt b=L/M;
const ltfatInt c=gcd(a, M,&h_a, &h_m);
const ltfatInt p=a/c;
const ltfatInt q=M/c;
const ltfatInt d=b/p;
/* division by d is because of the way FFTW normalizes the transform. */
scaling=1.0/sqrt(M)/d;
sbuf = ltfat_malloc(2*d*sizeof*sbuf);
/* Create plan. In-place. */
p_before = LTFAT_FFTW(plan_dft_1d)(d, (LTFAT_COMPLEX*)sbuf, (LTFAT_COMPLEX*)sbuf,
FFTW_BACKWARD, FFTW_MEASURE);
const ltfatInt ld3=c*p*q*R;
gfp=(LTFAT_REAL*)gf;
for (ltfatInt r=0; r<c; r++)
{
for (ltfatInt w=0; w<R; w++)
{
for (ltfatInt l=0; l<q; l++)
{
for (ltfatInt k=0; k<p; k++)
{
negrem=positiverem(k*M-l*a,L);
for (ltfatInt s=0; s<2*d; s+=2)
{
sbuf[s] = gfp[s*ld3]*scaling;
sbuf[s+1] = gfp[s*ld3+1]*scaling;
}
LTFAT_FFTW(execute)(p_before);
for (ltfatInt s=0; s<d; s++)
{
rem = (negrem+s*p*M)%L;
LTFAT_REAL* gTmp = (LTFAT_REAL*) &(g[r+rem+L*w]);
gTmp[0] = sbuf[2*s];
gTmp[1] = sbuf[2*s+1];
}
gfp+=2;
}
}
}
}
/* Clear the work-array. */
ltfat_free(sbuf);
LTFAT_FFTW(destroy_plan)(p_before);
}
LTFAT_EXTERN void
LTFAT_NAME_REAL(iwfac)(const LTFAT_COMPLEX *gf, const ltfatInt L, const ltfatInt R,
const ltfatInt a, const ltfatInt M, LTFAT_REAL *g)
{
ltfatInt h_a, h_m;
ltfatInt rem, negrem;
LTFAT_REAL scaling, *sbuf, *gfp;
LTFAT_FFTW(plan) p_before;
const ltfatInt b=L/M;
const ltfatInt c=gcd(a, M,&h_a, &h_m);
const ltfatInt p=a/c;
const ltfatInt q=M/c;
const ltfatInt d=b/p;
/* division by d is because of the way FFTW normalizes the transform. */
scaling=1.0/sqrt(M)/d;
sbuf = ltfat_malloc(2*d*sizeof*sbuf);
/* Create plan. In-place. */
p_before = LTFAT_FFTW(plan_dft_1d)(d, (LTFAT_COMPLEX*)sbuf, (LTFAT_COMPLEX*)sbuf,
FFTW_BACKWARD, FFTW_MEASURE);
const ltfatInt ld3=c*p*q*R;
gfp=(LTFAT_REAL*)gf;
for (ltfatInt r=0; r<c; r++)
{
for (ltfatInt w=0; w<R; w++)
{
for (ltfatInt l=0; l<q; l++)
{
for (ltfatInt k=0; k<p; k++)
{
negrem=positiverem(k*M-l*a,L);
for (ltfatInt s=0; s<2*d; s+=2)
{
sbuf[s] = gfp[s*ld3]*scaling;
sbuf[s+1] = gfp[s*ld3+1]*scaling;
}
LTFAT_FFTW(execute)(p_before);
for (ltfatInt s=0; s<d; s++)
{
rem = (negrem+s*p*M)%L;
g[r+rem+L*w] = sbuf[2*s];
}
gfp+=2;
}
}
}
}
/* Clear the work-array. */
ltfat_free(sbuf);
LTFAT_FFTW(destroy_plan)(p_before);
}
LTFAT_EXTERN void
LTFAT_NAME(iwfacreal)(const LTFAT_COMPLEX *gf, const ltfatInt L, const ltfatInt R,
const ltfatInt a, const ltfatInt M, LTFAT_REAL *g)
{
ltfatInt h_a, h_m;
LTFAT_FFTW(plan) p_before;
const ltfatInt b=L/M;
const ltfatInt c=gcd(a, M,&h_a, &h_m);
const ltfatInt p=a/c;
const ltfatInt q=M/c;
const ltfatInt d=b/p;
/* This is a floor operation. */
const ltfatInt d2= d/2+1;
/* division by d is because of the way FFTW normalizes the transform. */
const LTFAT_REAL scaling=1.0/sqrt(M)/d;
LTFAT_REAL *sbuf = ltfat_malloc( d*sizeof*sbuf);
LTFAT_COMPLEX *cbuf = ltfat_malloc(d2*sizeof*cbuf);
/* Create plan. In-place. */
p_before = LTFAT_FFTW(plan_dft_c2r_1d)(d, cbuf, sbuf, FFTW_MEASURE);
const ltfatInt ld3=c*p*q*R;
/* Advancing pointer: Runs through array pointing out the base for the strided operations. */
const LTFAT_COMPLEX *gfp = gf;
for (ltfatInt r=0; r<c; r++)
{
for (ltfatInt w=0; w<R; w++)
{
for (ltfatInt l=0; l<q; l++)
{
for (ltfatInt k=0; k<p; k++)
{
const ltfatInt negrem=positiverem(k*M-l*a,L);
for (ltfatInt s=0; s<d2; s++)
{
cbuf[s] = gfp[s*ld3]*scaling;
}
LTFAT_FFTW(execute)(p_before);
for (ltfatInt s=0; s<d; s++)
{
g[r+(negrem+s*p*M)%L+L*w] = sbuf[s];
}
gfp++;
}
}
}
}
/* Clear the work-arrays. */
LTFAT_SAFEFREEALL(cbuf,sbuf);
LTFAT_FFTW(destroy_plan)(p_before);
}
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